On 06/08/2018 12:36 PM, flihp wrote: > On 06/04/2018 12:55 PM, Jarkko Sakkinen wrote: >> On Thu, May 31, 2018 at 04:29:09PM -0700, Tadeusz Struk wrote: >>> The TCG SAPI specification [1] defines a set of functions, which allows >>> applications to use the TPM device in either blocking or non-blocking fashion. >>> Each command defined by the specification has a corresponding >>> Tss2_Sys_<COMMAND>_Prepare() and Tss2_Sys_<COMMAND>_Complete() call, which >>> together with Tss2_Sys_ExecuteAsync() is designed to allow asynchronous >>> mode of operation. Currently the driver supports only blocking calls, which >>> doesn't allow asynchronous operation. This patch changes it and adds support >>> for nonblocking write and a new poll function to enable applications using >>> the API as designed by the spec. >>> The new functionality can be tested using standard TPM tools implemented >>> in [2], with modified TCTI from [3]. >> >> I would need some statistics before I have interest to take these >> changes in any form eg use case where this matters in the end. > > The use cases motivating this feature are the same ones that motivated > the non-blocking behavior of other kernel interfaces (files, sockets and > other hardware) that has the potential to block threads in a process. By > implementing this same behavior in the TPM driver our goal is to enable > use of the TPM in programming languages / frameworks implementing an > "event-driven" model. There are a lot of them out there but since the > TSS2 APIs are currently limited to C our example code is in glib / GSource. > > Hopefully this is sufficient but if it isn't it would help us to get > additional details on what you're looking for. I tried to run some tests w/r/t blocking to non-blocking. and for example for tpm2_createprimary (type RSA) it looks more less like this: blocking: real 0m3.194s user 0m0.052s sys 0m0.094s vs nonblocking: real 0m1.031s user 0m0.043s sys 0m0.162s that's on Minnowboard Turbot D0 PLATFORM running FW Version: MNW2MAX1.X64.0097.R01.1709211204 The number are different every time I run it though. Is this what you wanted to see? Thanks, -- Tadeusz
